The art of carpentry has a long history, most of which employed the use of hand-powered tools such as a cross-cut hand saw. In using such a saw to cut lumber at an angle to the grain, carpenters have employed saw guides known as miter boxes to position the saw blade with regard to the work to be cut.
Although hand-powered carpenters, tools are still employed, their use has slowly given way to the use of powered tools driven by electric, pneumatic, or other power sources. These powered tools, including power saws, take various forms such as radial saws (also sometimes called radial arm saws), table saws, band saws and circular saws. By far, the most portable of these powered saws is the circular saw, which is well known in the art and conventionally powered by an electric or pneumatic source. These circular saws, which come in different saw blade sizes such as the six and one-half inch, seven inch, seven and one-quarter inch, seven and one-half, eight, eight and one-quarter, ten and one-quarter and sixteen inch saw blade sizes, are portable, permitting their use at a job site by journeymen carpenters as well as finding increased acceptance by the do-it-yourself homeowner or apartment dweller who has only an occasional need to cut lumber.
It has been customary in the past to scribe the lumber with a mark which acts as a guide for aligning either the blade, or a guide provided for this purpose on the saw, when using a powered saw to cut lumber. This prior practice is disadvantageous for several reasons. Firstly, the lumber must be scribed along its entire portion of the section to be cut, which introduces error not only in the measurement and scribing of the mark, but also entails the additional step of accurately scribing the position of the cut. Secondly, the accuracy of the cut along the scribed mark depends to a great degree not only on the skill of the carpenter to accurately align the saw blade, or guide on the saw, with the scribed mark, but also his skill in preventing deviation of the saw cut from its intended course as the saw blade traverses the work.
Thus, it would be advantageous to employ a guide means for the circular saw in a manner similar to that provided by the miter box for use with the hand saw.
Various attempts to provide a guide for power saws have been made in the past as illustrated in U.S. Pat. No. 2,595,322. Therein is disclosed a device for guiding a power saw at various angles ranging from 45 degrees to the grain of the lumber to normal to the grain. The device was adapted to mount to a conventional miter box of the type employed for use with hand saws, and had significant drawbacks. Among these are that the width of the work to be cut is limited by the size of the conventional miter box, and as the width of the miter box increased to accommodate larger width lumber, the size of the miter guide approximately doubled, producing an unduly heavy and cumbersome miter guide with ineffective cutting width for its size and an angular limitation of only 45 degrees to the grain of the lumber.
Additional attempts at providing a portable miter box for use with power-driven saws is illustrated in U.S. Pat. No. 2,633,162, but suffered from the same disadvantages of being unduly cumbersome in size and weight and being limited to a 45 degree angular cut to the direction of the grain of the lumber. Further attempts at providing a guide or support for power saws can be found in U.S. Pat. Nos. 2,770,265; 2,803,271 and 3,066,710. None of these devices overcame the problems of an unduly heavy construction of the guide and limited width and angular cut of the workpiece.
By far, the best attempt at providing a portable table for a circular saw is illustrated in U.S. Pat. No. 3,195,591, the entire disclosure of which is herein incorporated by reference. This disclosure provides a portable table which is a segment of a semi-circle having a pivoted saw guide, wherein the saw blade is traversable along the length of the table from an area near its outer peripheral edge through the pivot portion of the saw guide. However, this device, like those of the prior art previously discussed, is limited in its angular cut to 45 degrees to the grain of the workpiece and its effective width of cut, although an improvement over the prior art previously discussed, is also limited by the construction of the portable table and the guide. Furthermore, the saw guide was not rigid because the locking depended on point contact of an adjustable threaded member applying pressure to the periphery of the table. This point contact prevented the maintenance of the guide means at its intended angular orientation to the workpiece. Additionally, this device did not permit the employment of power saws of various saw blade sizes, nor did its construction facilitate storage of the table when not in use. The ease of storage is an important consideration, especially for the apartment dweller who normally has limited storage areas, such as small closets or storage bins.
Thus, despite a long-felt need in the art, there has not been provided a portable table for guiding power tools, such as a circular saw, that provides a large angular cut relative to the grain of the workpiece and yet is compact, facilitating its storage.